<template>
    <div>
        <router-link 
        tag="div" to="/" 
        class="header-abs"
        v-show="showAbs">
            <div class="iconfont header-abs-back">&#xe624;</div>
        </router-link>
        <div class="header-fixed" 
        v-show="!showAbs"
        :style="opacityStyle"
        >
            <router-link  to="/">
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
        景点详情</div>
    </div>
</template>
<script>
export default {
    name :'DetailHeader',
    data () {
        return{
            showAbs :true,
            opacityStyle: {
                opacity :0
            }
        }
    },
    methods :{
        handleScroll () {
            const top =document.documentElement.scrollTop
            if(top > 60 ) {
                let opacity = top/140
                opacity = opacity > 1 ? 1:opacity
                this.opacityStyle = {
                    opacity
                }
                this.showAbs = false
            }else{
                this.showAbs =true
            }
        }
    },
    activated (){
        window.addEventListener('scroll',this.handleScroll)
    },
    deactivated (){
        window.removeEventListener('scroll',this.handleScroll)
    }
}
</script>
<style lang="stylus" scoped>
     @import '~styles/varibles.styl';
    .header-abs
        position :absolute
        left :.2rem
        top :.2rem
        width :.8rem
        height :.8rem
        line-height :.8rem
        text-align :center
        border-radius :.4rem
        background :rgba(0,0,0,.8)
        .header-abs-back
            color :#fff
            font-size :.4rem
    .header-fixed  
        position :fixed
        top :0
        left :0
        right :0
        height :$headerHeight
        line-height :$headerHeight
        text-align :center
        color :#fff
        background :$bgColor
        font-size :.32rem
        .header-fixed-back
            position :absolute
            top:0
            left :0
            width :.64rem
            text-align :center
            font-size :.4rem
            color :#fff
       

</style>

